Patent GB-287649-A (GB)
Title: Improvements in or relating to valves or closure devices for controlling the flow of liquids
IPC: F16K15/03
Filed: 1927-01-03
Abstract: 287,649. Blakeborough, R. A., Brown, J. r., and Tart, H. Jan. 3, 1927. Fluid-actuated valves.-A reflux or non-return valve adapted to close automatically on a reversal of flow or on a predetermined drop in pressure or velocity of flow, has a valve member pivotally mounted in a casing, so that when the valve is fully open the passage way through the casing is unobstructed and forms a continuation of the bore of the conduit. In the form shown in Fig. 1, the valve, member is mounted on a shaft c arranged in a pocket a<1> and extending to the outside of the casing where it is provided with an arm d. The arm d has a projecting pin c normally engaged by a hook f<1> formed on one arm f of a counterweighted lever h. A tumbler weight i<2> is normally held in a raised position by a catch j actuated by a counterweighted paddle k<1> in the fluid conduit, but when released it falls on the arm h<a> of the lever h to release the hook f and allow the valve to close. The tumbler may be controlled by a piston or diaphragm subject to conduit pressure and when used in a condenser system may be further controlled by a second diaphragm subject to the vacuum produced by the air pump. Fig. 7 shows a modification in which means are provided to reset the device automatically when pressure is restored in the pipe line. The valve is normally held in its open position by a counterweighted hook 16 engaging a roller 15 carried by an arm fixed to the valve spindle c. A tumbler 22 pivoted on a shaft 20 is normally held in its raised position by a counterweighted catch 28, which catch is released by a weighted lever 24 when conduit pressure acting on a valve member 46 falls. The tumbler in falling engages an arm 19 connected by a link 18 to the hook and so releases the catch and allows the valve to close. The main valve is moved to its open position by a power cylinder acting through a rack 34<2> and toothed quadrant 35 pivoted on the shaft c and adapted to engage a lug 36 to open the valve and move the roller 15 into engagement with the hook 16. At the same time a projection 39 on a toothed wheel 38 connected by an idle wheel 37 with the quadrant engages the tumbler to move it into its raised position. The pressures acting in the power cylinder and also on a piston. 45 coupled to the valve 46 are controlled by a pair of interconnected cocks 29, 30 coupled by a link 28 to an arm 27 pivoted on the shaft c. Conduit pressure is supplied to both cocks by a pipe 31, and exhausted through connections 29<3> and 30<4>. The cock 30 has connections to each end of the power cylinder and the cock 39 has a connection with the chamber 32<1> below the piston 45. As the main valve closes an am 26 connected to the lever d! moves the lever 27 so as to reverse the cocks 29 and 30, so that when pressure is re-established pressure is admitted beneath the piston 45 to raise the lever 24 and permit the catch 23 to return to its operative position and to the right hand end of the power cylinder to move the main valve to its open position. As the main valve reaches its open position a roller 41 on a disc 40 connected to the wheel 38 releases a counterweighted catch 42 to release a second tumbler 43. This falls on an arm 49 connected to the link 28 and again reverses the control valves, so connecting the chamber 32<1> to exhaust and moving the piston back to its normal position. This movement of the piston restores the tumbler 43 to its raised position. The apparatus can be tested by manipulating the hand lever 49. In a modification the valve is actuated by a power cylinder acting through chain gearing and clutch mechanism under the control of a weighted auxiliary valve actuated by conduit pressure.